1,721,000 research outputs found
Tolerance design of closed-loop controllers for DC-DC voltage regulators: Genetic algorithms & vertex analysis based optimization
No full textIn this paper nominal and tolerance design of feedback compensation networks for dc-dc switching converters is presented. Tolerance design techniques, recently presented by the authors and briefly summarized in this paper, are adopted to achieve an optimal design of the compensation network. A Genetic Algorithm seeks for the set of commercial parameters and tolerance values of the RC components such that the compensation network fulfils design constraints on the acceptability ranges of loop gain cross-over frequency and phase margin. Phase margin and pole-zero matching methods are adopted to generate nominal design solutions using two types of compensation networks. Such solutions are considered as guesses for the tolerance design performed. The population of design solutions evolves towards different optimal final projects depending on the required design preferences. Vertex Analysis has been used to check the feasibility of each candidate tolerance region. Moreover, at the end of the design process, the yield value of the optimal solution selected by the genetic algorithm is calculated by means of an Interval Arithmetic-based procedure. The results presented in this paper, even though concerning the optimal design of the compensation network of buck dc-dc converter, are quite general and show how the techniques used can greatly support designer decisions
Optimal Coils and Control Matching in Wireless Power Transfer Dynamic Battery Chargers for Electric Vehicles
No full textWireless Power Transfer (WPT) is a key enabling technology towards the transportation electrification, able to overcome some limits of the plug-in charging of the Electric Vehicle (EV). In this frame, a special attention is paid to the dynamic WPT systems, where the EV is recharged during motion. This paper presents a model and a resultant method for the system level design of a series-series WPT Dynamic Battery Charger (WPT-DBC) for EVs. The model allows analyzing the joined influence of coil pair characteristics and power converter stages controls on the global performances of WPT-DBCs. The design method provides general guidelines for system level optimization, matching the characteristics of the power and control elements of a series-series WPT-DBC, to achieve the desired efficiency, receiver power loss and battery charge
GaN Power Transistors Behavioral Modeling
No full textThis paper discusses the behavioral modeling of Gallium Nitride (GaN) power transistors for the analysis of voltage/current waveforms and losses in hard-switching Switch-Mode Power Supplies (SMPSs), with main emphasis on the I-V and C-V characteristics. A new technique extending the I-V characteristics to high drain-source voltage is presented. Two different capacitance models are also compared. The proposed models are fully based on device datasheet curves and have been implemented in PathWave Advanced Design System software, allowing easy construction of symbolically defined devices. A 350 V/3 A boost converter is considered as a case study, with a half-bridge of two 650 V-30 A GaN power transistors
Power Losses Analysis of SiC MOSFETs in DC-DC Converters with High-Ripple-Current Inductors
No full textThis paper discusses behavioral models for power losses analysis of Silicon Carbide (SiC) MOSFETs in DC-DC converters, with emphasis on the impact of inductor saturation and peak-peak ripple current. All models are implemented in PathWave ADS software, by using symbolically defined devices. A PV-MPPT DC-DC boost converter is considered as a reference case study. The results confirm the advantages of working with large peak-peak ripple and partial saturation of power inductors
Exploiting Saturable Inductors in SEPIC Regulators
No full textThis paper discusses the use of saturable power inductors in Separated Inductor Single-Ended Primary Inductor Converter (SI-SEPIC) regulators. To ensure control stability, the input and output inductors in a SI-SEPIC regulator must be selected with an inductance ratio fitting suitable constraints, which may lead in turn to large output inductance in applications with step-up voltage conversion ratio. The method and the results presented in this paper show that using saturable ferrite inductors allows to reduce the size of these components, while providing larger inductance in low-load operation, thus helping in discontinuous conduction mode prevention and overall efficiency increase. The results are validated by means of simulation tests performed on a 9V/1.5A SI-SEPIC regulator
Polarization and depolarization currents in carbon-black loaded polyolefins
No full textIn this paper the first results concerning an experimental investigation of the conduction mechanism in heat shrinkable carbon black-loaded polyolefins are reported by considering the dependence of charging and discharging currents on the adopted electrode material and specimen dimensions. Data concerning applied electrical stresses comparable with those encountered in service are discussed by considering models proposed in the literatur
Method, Test Procedure and System for the Experimental Characterization of Power Inductors
No full textThis paper discusses a novel patented approach for the experimental characterization of power inductors, operating under the typical operating conditions of hard-switching DC-DC power converters. The proposed approach is based on the application of a target performance tracking concept, realized using the 'perturb-and-observe' criterion. The methodology is inherently safe and automatizes the detection of the subset of feasible operating conditions ensuring that the component under test fits a given performance target. The results presented in this paper refer to the characterization of two commercial power inductors and show the wide range of power converter optimization opportunities offered by the new patented approach
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